How to Grow Cucumbers From Seed

cucumber seedlings in a pot

The Spruce / Margot Cavin

There's nothing quite as satisfying as the crunch of a fresh, cool cucumber on a hot summer day. They are good for snacks, salads, and even skincare. Cucumbers also can be added to water for light flavoring. And when the summer is coming to a close, you can pickle the rest of the harvest to enjoy all year long. Although cucumbers can run into issues with pests, they are still pretty easy to grow. Here’s how to start cucumbers from seed for your garden.

How to Grow Cucumbers

Cucumbers need warm temperatures, so seeds should be started outdoors when the soil has warmed to around 70 degrees Fahrenheit and there's no chance of frost. Seeds also can be started indoors about a month before your area's last projected frost date in the spring.

Cucumbers are traditionally planted in rows or on mounds and allowed to sprawl along the ground. Be aware that as a member of the pumpkin and gourd family, cucumber plants can take up quite a bit of space. But they also can be trained to climb a fence, trellis, or other sturdy support structure for a more contained growing site.

Plant seeds 1/2 inch deep and 6 to 10 inches apart. Once they've sprouted, thin them to 1.5 to 2 feet apart. Water frequently, never allowing the soil to dry out but also making sure the plants aren't waterlogged. Cucumbers are mostly water, so it’s very important to keep them sufficiently watered.

Harvest cucumbers when they are fairly small. Letting them grow too big will affect flavor and quality. Plus, if just one cucumber grows long enough that the seeds become mature, the entire plant will stop producing cucumbers. So pick them frequently to keep the plant growing and the harvest coming.

planting cucumber seeds

The Spruce / K. Dave

cucumber seedlings

The Spruce / K. Dave

cucumber seedlings

The Spruce / K. Dave

cucumber preparing to fruit
​The Spruce / Margot Cavin
cucumbers ready for harvest

The Spruce / K. Dave

Cucumber Pests and Diseases

Like all gourds, cucumbers are prone to pests and diseases if not tended carefully. The first line of defense is choosing a good variety. Asian cucumbers, for example, are more disease resistant than larger varieties. 'Straight Eight' is resistant to the mosaic virus, a common cucumber malady. And 'Tasty Jade' is another Asian variety that grows well on a trellis, which can raise it above pests and diseases in the soil and lower the plant's risk of being impacted. Planting seeds too early or too close together also can invite mosaic virus and stem rot.

The cucumber beetle is the most likely pest to target your crop. Parasitic nematodes can help curb them, as well as simply picking them off. Tansies have been shown to deter cucumber beetles, too, so they could be worth planting by your cucumber crop.

One major key to avoid pests and diseases lies in crop rotation. If you have heavy feeding, pest-attracting gourds in the same place season after season, they will be prone to problems. Try to plant cucumbers after spinach or legumes, and follow them with a nitrogen-fixing ground cover, such as clover, during the winter.